Cells in a team
Cells joined positive to negative make a battery.
Two cells in a row
A torch often holds two cells in a row. Both go in the tray. But what if one cell is put in turned round, so the two caps face each other?
Will the torch lamp glow?
What this lesson covers
The idea
A battery is a combination of two or more cells in which the positive terminal of one cell is connected to the negative terminal of the next; more cells give more energy and/or energy for longer.
Two cells in a row
A torch often holds two cells in a row. Both go in the tray. But what if one cell is put in turned round, so the two caps face each other?
Will the torch lamp glow?
- Yes, brighter than with one cell
- No, it stays dark
- Yes, but dimmer
Fix the torch
The lamp is dark. Tap a cell to turn it round. Then use Add a cell to put a third in the tray.
Plus to minus
A battery is a combination of two or more cells in which the positive terminal of one cell is connected to the negative terminal of the next. More cells give more energy and/or energy for a longer time.
In a real torch, a thick wire or metal strip joins the + of one cell to the – of the next. The word "battery" is also used for a single cell, like the one that powers a mobile phone.
- Cells in the tray | Lamp
- 1 cell | glows
- 2 cells, + touching – | brighter
- 3 cells, + touching – | brightest
- 2 cells, + touching + (or – touching –) | dark
Notes
A battery is two or more cells joined + to –. More cells give more energy and/or energy for a longer time.
Check yourself
To form a battery, the + terminal of one cell must touch the _ terminal of the next cell.
What do we call two or more cells joined together, + to –?
Why do many torches use more than one cell?
A torch holds 3 cells joined correctly in a row. In how many places does a + terminal touch a – terminal?
Answer: 2
3 cells make 2 joints. Each joint is a + touching a –.
- positive. Two + terminals touching push against each other.
- negative — correct. Yes! Positive of one to negative of the next.
- metal body. Only terminals are joined.
- A circuit. A circuit is the complete path. The cells together are a battery.
- A battery — correct. Yes! A battery.
- A switch. A switch opens and closes the path. It is not a group of cells.
- To give the circuit more energy, or energy for a longer time — correct. Yes! More cells give more energy and/or a longer supply.
- To make the torch heavier. Weight is not the reason.
- So that the lamp has two terminals. The lamp has its own two terminals. The cells are for energy.