IMSO 2007 Science International - Experiment

### FUN WITH DIGITALS

Name: ___; Country: ___. Jakarta, Indonesia, Wednesday, 14 November 2007. The complete experimental examination lasts 120 minutes.

Mrs. Ana is driving her new car which is equipped with a good safety system. The engine of the car can only be started if its doors are locked and the seat belt is fastened. If both conditions are not fulfilled, the engine cannot be started. In science, these conditions are described as the “AND” logic.



Many buildings are equipped with fire detection alarm system. The alarm will be automatically turned on if the system detects smoke, or the fire alarm button is pushed. The alarm will turn on if at least one of the above conditions is fulfilled. In science, these conditions are described as the “OR” logic.



There are many electric appliances such as lamps, refrigerators, TV and so on in our homes that are equipped with switches to turn them on and off. If the switch is in the ON position, those appliances will turn on because electric current can flow through them.

Now, we shall play with circuit board. The lamp will be turned on and off with the help of digital circuits with “AND” logic and “OR” logic principles using switches.

### Provided electronic kits

Item 1. One set of main board consisting of:
- (a) a socket for extension board;
- (b) a main lamp (actually it is a LED, light emitting diode);
- (c) indicator lamps (LEDs);
- (d) four switches (S1, S2, S3, “AND” S4);
- (e) a buzzer;
- (f) batteries in a black box.



Picture labels: indicator lamps; battery switch; main lamp; batteries; socket; switches.

Item 2. Five extension boards (logic boards):



**Editorial practical note:** Use only the supplied low-voltage battery kit. Switch off the batteries before changing boards; align pins gently. Do not connect this kit to household mains. ON and OFF are retained as the required table entries. Board Z appears later but is absent from the list of five boards; its availability must be checked.

### ACTIVITY 1

Step 1. Plug the pins found at the bottom of Board A (“AND” logic) into the socket on the main board properly (see the picture below).



Step 2. Switch on the batteries. Batteries are working properly if the red indicator lamp lights up.

Step 3. The logic board is working properly if the green indicator lamp lights up.

Step 4. In this activity, you will have to change the positions of S1 and S2 switches to ON or OFF according to Table 1 below. Do not use S3 and S4. Write “ON” in the Main Lamp column (L) if the main lamp lights up; write “OFF” if the main lamp does not light up.

Table 1. Board A (AND)

| No. | S1 | S2 | Main lamp L |
| --- | --- | --- | --- |
| 1 | OFF | OFF | ___ |
| 2 | OFF | ON | ___ |
| 3 | ON | OFF | ___ |
| 4 | ON | ON | ___ |

(Total score 4)

Step 5. When you have completed Table 1, switch off the batteries.

### ACTIVITY 2

Step 1. Remove Board A and plug in Board B (OR logic).

Step 2. Repeat Activity 1.

Table 2. Board B (OR Logic)

| No. | S1 | S2 | Main lamp L |
| --- | --- | --- | --- |
| 1 | OFF | OFF | ___ |
| 2 | OFF | ON | ___ |
| 3 | ON | OFF | ___ |
| 4 | ON | ON | ___ |

(Total score 4)

**Question 1.** From Tables 1 and 2, what is your conclusion on how the “AND” logic and the “OR” logic work? Answer: ___ (Score 4)

### ACTIVITY 3

You are requested to find the unknown logics (X1 and X2) on Board C.

Step 1. Remove Board B and plug in Board C.

Step 2. Repeat Activity 1 by using S1, S2 and S3 only. Do not use S4.

Table 3. Board C

| No. | S1 | S2 | S3 | Main lamp L |
| --- | --- | --- | --- | --- |
| 1 | OFF | OFF | OFF | ___ |
| 2 | OFF | OFF | ON | ___ |
| 3 | OFF | ON | OFF | ___ |
| 4 | OFF | ON | ON | ___ |
| 5 | ON | OFF | OFF | ___ |
| 6 | ON | OFF | ON | ___ |
| 7 | ON | ON | OFF | ___ |
| 8 | ON | ON | ON | ___ |

(Score 4)



**Question 2.** Use Table 3 to answer:

(a) What is the logic of X1, is it “AND” or “OR”? Explain your answer. (Score 2)

(b) What is the logic of X2, is it “AND” or “OR”? Explain your answer. (Score 2)

### ACTIVITY 4

You are requested to find the unknown logics (X3, X4 and X5) on Board D.

Step 1. Remove Board C and plug in Board D.

Step 2. Repeat Activity 1 by using S1, S2, S3 and S4.



Table 4. Board D

| No. | S1 | S2 | S3 | S4 | Main lamp L |
| --- | --- | --- | --- | --- | --- |
| 1 | OFF | OFF | OFF | OFF | ___ |
| 2 | OFF | OFF | OFF | ON | ___ |
| 3 | OFF | OFF | ON | OFF | ___ |
| 4 | OFF | OFF | ON | ON | ___ |
| 5 | OFF | ON | OFF | OFF | ___ |
| 6 | OFF | ON | OFF | ON | ___ |
| 7 | OFF | ON | ON | OFF | ___ |
| 8 | OFF | ON | ON | ON | ___ |
| 9 | ON | OFF | OFF | OFF | ___ |
| 10 | ON | OFF | OFF | ON | ___ |
| 11 | ON | OFF | ON | OFF | ___ |
| 12 | ON | OFF | ON | ON | ___ |
| 13 | ON | ON | OFF | OFF | ___ |
| 14 | ON | ON | OFF | ON | ___ |
| 15 | ON | ON | ON | OFF | ___ |
| 16 | ON | ON | ON | ON | ___ |

(Score 4)

**Question 3.** Use Table 4 to answer:

(a) What is the logic of X4, is it “AND” or “OR”? (Score 1)

(b) What is the logic of X3, is it “AND” or “OR”? (Score 1)

(c) What is the logic of X3, is it “AND” or “OR”? (Score 1)

**Source note:** Part (c) repeats X3 in the printed question. The activity also asks for X5. The wording is preserved; ask the supervisor whether part (c) is intended to ask for X5.

### ACTIVITY 5

You are requested to find the unknown logics (X6, X7 and X8) on Board E.

Step 1. Remove Board D and plug in Board E.

Step 2. Repeat Activity 1 by using S1, S2, S3 and S4.



(You could use a table if necessary.)

**Question 4.**

(a) What is the logic of X6, is it “AND” or “OR”? (Score 1)

(b) What is the logic of X7, is it “AND” or “OR”? (Score 1)

(c) What is the logic of X8, is it “AND” or “OR”? (Score 1)

### ACTIVITY 6

In this activity, you are requested to fill in the blank in Table 6, based on the combination of two “OR” logics and one “AND” logic as shown below.



Table 6

| No. | S1 | S2 | S3 | S4 | L |
| --- | --- | --- | --- | --- | --- |
| 1 | OFF | ___ | ON | OFF | OFF |
| 2 | ON | OFF | ON | OFF | ___ |
| 3 | ON | ON | ___ | ON | OFF |

(Score 3)

### ACTIVITY 7

In this activity, you are requested to fill in the blank in Table 7 based on the combination of one “OR” logic and two “AND” logics as shown in the diagram below.



Table 7

| No. | S1 | S2 | S3 | S4 | L |
| --- | --- | --- | --- | --- | --- |
| 1 | ___ | ___ | ___ | ___ | ON |
| 2 | ___ | ___ | ___ | ___ | ON |
| 3 | ___ | ___ | ___ | ___ | ON |

(Score 6)

### ACTIVITY 8

Step 1. Unplug Board E and plug in Board Z into the socket in the main board properly.

Step 2. The Buzz will create a sound only for a single combination of switches S1, S2, S3 and S4. In this activity, you have to find the right combination for the switches by writing “ON” and “OFF” in the table below.

| S1 | S2 | S3 | S4 | Buzz |
| --- | --- | --- | --- | --- |
| ___ | ___ | ___ | ___ | ON |

(Score 2)

### Playing with Yeast Ball

**Editorial safety and source note before practical work:** This historical paper does not identify the organic materials or indicator chemically. A supervising adult must verify the supplied materials and their safe use. Do not taste the mixtures or inhale powders. Avoid skin/eye contact with the indicator and wash hands. An adult should handle hot water; check temperature with the thermometer. Do not block or fully seal the gas outlet: fermentation gas must be able to move the indicator and escape safely. Keep the apparatus away from flames. The source's reassurance about indicator contamination is not a general safety claim. The source prints approximately 40⁰ Celsius (40 °C), not 400 °C. Its materials list and tables name A and B, but Part A additionally names C; no identity, supply or table for C is given. Ask the supervisor before using an additional sample.

### Introduction

Fermentation is a process to break down organic material such as fat, carbohydrate and protein into more simple substances. Fermentation in general is caused by microorganisms such as yeast, bacteria or fungus. Fermentation needs organic materials and water to keep the microorganisms alive.

Temperature is also an important factor in the process of fermentation. For example, inactive yeast can be activated rapidly if fermentation condition occurs under approximately 40⁰ Celsius.

The production of a gas during fermentation is caused by the types of substrate used. In most cases fermentation does not require oxygen so that an enclosed condition can be used for process.

### Instruction: materials and equipment

In this experiment you will be provided with 4 small containers. Three of them have a hole on their lid. One of the containers contains color indicator. You can put the indicator into the plastic tube by tapping the tip of the plastic tube into the color indicator. You can observe the fermentation activity based on movement of the indicator. Ignore if the color indicator contaminating your mixture, fermentation will not be affected! [This is the source's statement, retained for fidelity; see the safety note above.]

A pen marker and a ruler can be used to mark the plastic tube. The markings on the plastic tube are used to measure the rate of fermentation. Make several markings on the plastic tube (refer to the tables given). A stop watch is also provided to measure the time.

Use 10 ml of warm water for each experiment by mixing hot water with fresh water in the plastic cup available. A thermometer is available to measure the fermentation temperature. **Beware of hot water!**

List of materials and equipment:

| Item | Materials and equipment |
| --- | --- |
| 1 | Small containers (3 pieces) |
| 2 | A container of color indicator |
| 3 | Plastic cups (2 pieces) |
| 4 | Plastic tubes (3 pieces, 1.5 meters each) |
| 5 | Spoons (4 pieces) |
| 6 | An adhesive tape |
| 7 | A vacuum flask of hot water |
| 8 | A bottle of freshwater |
| 9 | A thermometer |
| 10 | A stopwatch |
| 11 | A plastic measuring cylinder, 15 ml size |
| 12 | A cotton towel |
| 13 | Organic materials (two packs: labeled A and B) |
| 14 | Two packs of yeast ball |
| 15 | A marker |
| 16 | Plasticine (toy clay) |
| 17 | Graph papers |

The ruler mentioned in the instructions is not separately listed in the numbered inventory. Check that one is available.



Editorial materials sketch only, not a proposed completed apparatus or experimental result. Labels A and B identify the source's supplied samples.

### PART A: Construct a fermentation device and prove that it works

Design a setup using materials and equipment available to show fermentation. Draw the setup on a paper and explain how it works. Use blank pages on the back of this exam paper if you need more space to draw and write explanation.

Answer: ___ (Score 5)

Perform the experiments based on what you have designed. Use organic materials A, B and C to measure fermentation rate. Wait for 3 to 5 minutes before you measure the fermentation. Record your results in the tables.

Number of markings in your plastic tubes: ___

Distance between two markings: ___

(Score for data recording: 8 points)

**Organic material A**

| Markings | Distance from starting point (cm) | Time (minutes) | Time (second) |
| --- | --- | --- | --- |
| 0 | 0 | 0′00″ | 0 |
| 1 | ___ | ___ | ___ |
| 2 | ___ | ___ | ___ |
| 3 | ___ | ___ | ___ |
| 4 | ___ | ___ | ___ |
| 5 | ___ | ___ | ___ |
| 6 | ___ | ___ | ___ |
| 7 | ___ | ___ | ___ |

**Organic material B**

| Markings | Distance from starting point (cm) | Time (minutes) | Time (second) |
| --- | --- | --- | --- |
| 0 | 0 | 0′00″ | 0 |
| 1 | ___ | ___ | ___ |
| 2 | ___ | ___ | ___ |
| 3 | ___ | ___ | ___ |
| 4 | ___ | ___ | ___ |
| 5 | ___ | ___ | ___ |
| 6 | ___ | ___ | ___ |
| 7 | ___ | ___ | ___ |

The source's B table omits its column headings; the identical headings from A are repeated here for readability. No data table for C is supplied. Blank cells are for actual measurements, not example results.

### Questions

(a) What are the important material(s) and condition(s) needed for fermentation?

Important material(s): ___

Condition(s): ___ (Score 3)

(b) In this experiment, how do you mix your organic materials with warm water without contaminating the other setups? Answer: ___ (Score 1)

(c) Why should you wait for 3 to 5 minutes before measuring the fermentation rate? Answer: ___ (Score 1)

### PART B: Analyze the effect of various organic material on the fermentation rate

(a) Draw graphs from the results of each setup (distance vs. time) on the same axes using the millimeter block sheet. (Score 2)

(b) Based on your graph what is the best organic material to be used for this fermentation reaction? Explain. (Score 2)