GoalSay what a buzzer and a motor do, and that more cells make a lamp brighter.
New words
buzzer · a part that makes a sound when electricity flows through itmotor · a part that spins when electricity flows through itbrighter · giving out more light
Explanation
Circuits can do more than light a lamp. A buzzer makes a sound when it is in a complete circuit. A motor spins, and it can turn a fan or a toy wheel. These only work when the circuit is complete. If we add more cells, the lamp is brighter. A motor spins faster and a buzzer is louder. Never use too many cells, because the lamp could break. Use only the number of small cells that your teacher or adult says. Never join a circuit to the mains.
Worked examples
This circuit has a buzzer. The circuit is complete, so the buzzer makes a sound.
This circuit has a motor. It is complete, so the motor spins. A motor can turn a small fan.
Rosa builds a circuit with one cell. Then she uses three cells and the same lamp. With three cells the lamp is brighter.
Class activity
Brighter test (with an adult, small cells only): build a circuit with one cell and a lamp. Predict what will happen with two cells. Change only the number of cells and keep the same lamp and wires. Look at how bright the lamp is each time. Write in a table: one cell, two cells, which is brightest. Stop if anything feels warm, and never use more cells than the adult says.
Practice
1
Which part would you put in a circuit to make a doorbell for a toy house?
A buzzer, because it makes a sound.
2
What is the part in this circuit, and what is it doing?
A motor. It is spinning, because the circuit is complete.
3
A lamp is joined to one cell. Mo adds another cell. What happens to the lamp?
It gets brighter.
4
Why must we never join a circuit to the mains?
Mains electricity is very strong and dangerous. We use only small cells.
